So I swapped in two new AGM batteries and the van starts in the cold now (but just barely). Since from my tests the glow plugs looked good I decided it was time to get a professional diagnosis.
Took the rig to AG, per MSD's recommend, they were pretty impressed with the condition of the van and the Quigley system, so that was nice to hear. What wasn't nice to hear was the fact that they're pretty sure its the injectors giving me trouble.
I knew this was an expensive problem and it seems they do an extensive job when replacing, but wow I don't think I can quite commit the quoted $8k for them to do it. Sooooo I'm exploring other options for the time. Does anyone have experience doing the injectors on a 7.3PSD Van? Does $8k sound about right for the work, I was expecting something closer to $6 (not that that is much better)?